Sen. Mary Landrieu, D-La. / Jim Hudelson, The (Shreveport, La.) Times

by Martha T. Moore and Catalina Camia, USA TODAY

by Martha T. Moore and Catalina Camia, USA TODAY

The debate over military intervention in Syria has exposed rifts in both political parties that could seep into campaigns in 2014 and beyond.

President Obama's request that Congress authorize strikes against Syria because of its use of chemical weapons has divided Democrats supporting the president from those who oppose the United States undertaking another Mideast military action. Republicans are split between those favoring an aggressive response to the Bashar Assad regime and the bloody civil war and libertarian-leaning conservatives who oppose an overseas intervention.

On Wednesday, the Senate Foreign Relations Committee voted to approve authorization, over the "no" votes of two possible GOP 2016 presidential candidates, Kentucky Sen. Rand Paul and Sen. Marco Rubio of Florida. Both the full Senate and House are likely to vote on the resolutions next week.

Whatever the outcome of the vote, Syria could be an issue in key Senate races next year, when Republicans hope to wrest six seats away from Democrats and take control of the chamber. "If (a war in Syria) gets complicated, then it could become a problem for everybody," says Jennifer Duffy of the Cook Political Report.

Arkansas Democratic Sen. Mark Pryor, considered vulnerable by Republicans, could support a president unpopular in his state by voting for authorization - he has some cover because his opponent, GOP Rep. Tom Cotton, endorsed military action in a Washington Post op-ed Wednesday. One state over, Sen. Mary Landrieu, D-La., is considered a prime target for Republicans, and voting with Obama may be hazardous for her in a state that he lost badly in the 2012 presidential election.

In Kentucky, where Democrats would like to unseat Republican Sen. Mitch McConnell, the Senate minority leader faces a Tea Party primary challenger who opposes military action. Neither Pryor nor McConnell have said how they would vote but have said they have questions about the president's plan.

McConnell may ultimately join with the rest of congressional leadership to support the authorization, but he must tread carefully because Paul - a hero of the Tea Party movement - is leading opposition from Republicans. "He needs that symbolic link between them," said political scientist Steve Voss of the University of Kentucky. "It's likely he just doesn't want to undermine his junior colleague's position by being too public in his support for the president. If he's going to break with an ally like that, he needs to make it clear he's done so carefully and thoughtfully."

Democratic candidate Alison Lundergan Grimes hasn't said how she might vote on Syria, but there is less pressure on her, Voss says. Democrats want to beat McConnell "so badly," she will be given party support no matter what her position on Syria. In addition, Voss said, swing voters in Kentucky "hate Obama, but they also tend to like a more muscular foreign policy. Siding with him on this one is not going to cost her a lot of political capital."

On all sides, the longer the United States remains engaged in Syria, the bigger a political liability a "yes" vote would become - as did the 2002 Iraq vote.

"These kinds of votes on war and peace and casualties, the proof is in the pudding and we won't know the pudding for three months, six months or longer," said political columnist Stuart Rothenberg.

Some political observers see the divide on Syria in terms of Washington insiders favoring Obama's position vs. outsiders who do not. "This is the establishment circling the wagons, but there are more outsiders at the table and grass roots â?¦ have an ability to express a louder voice than in 2008,'' says Matt Kibbe, president of FreedomWorks, a Tea Party-aligned group that does not take positions on foreign policy matters. Opinion surveys show Americans oppose military intervention in Syria, he points out.

"The verdict on this is already pretty clear from voters: They do not want to see another conflict," Kibbe says. "Politically, the bottom line is, I think anybody that's up in 2014 ignores that at their peril.''

Democratic voters who oppose military action may be less likely to punish candidates who side with Obama. "I'm not sure the anti-war movement at this point in time has what it takes to give many members heartache over this," says Jim Manley, former Senate aide and now Democratic political consultant.

But no politician can ignore the fact that a vote on military action can be a powerful weapon for an opponent. The obvious example: In 2008, presidential candidate Hillary Rodham Clinton was forced to defend her Senate vote in favor of war with Iraq by her top rival Barack Obama, who was the anti-war candidate in the Democratic primary.

Now, Republican criticism of the Obama administration's previous handling of Syria is implicit criticism both of the former secretary of State and Vice President Biden, both potential contenders in 2016.

"Votes you take on issues related to war will stay with you forever," Manley said.

Even if voters are more worried about pocketbook issues next year than foreign affairs, "these members are going to think that the vote that they're going to cast on this resolution could have staying power into the next election. And that's all that matters," Rothenberg says.